Evolution and Structural Basis of Curcuminoid and Gingerol Formation in Turmeric and Ginger

植物代谢的两个重要问题是：植物产生大量化合物的机制是什么？这些机制是如何进化的？姜和姜黄含有大量结构相似的化合物，似乎是由相同的生化途径产生的。这些化合物，包括姜黄素、其他二芳基庚烷、姜辣素和姜辣素样化合物，是由聚酮合成酶样酶（PKSs）产生的。由于这两个物种产生大量相关化合物，因此它们是研究植物中这些化合物产生差异的分子和结构基础的理想系统。选择这些化合物作为本项目的重点是因为它们对植物防御、植物适应环境和人类健康的重要性，并且因为在生姜和姜黄中已经发现了一组与已知的PKSs（如查尔酮合成酶）相关但不同的基因（迄今为止共41个），这些基因在两种物种的组织和发育阶段之间表达差异。该项目将重点确定该基因家族的哪些特定成员负责产生特定的姜黄素、姜辣素、其他二芳基庚烷或姜辣素相关化合物。它还将确定姜或姜黄中单个PKSs的生化功能。然后，该项目将确定不同PKSs之间不同活动的结构基础。这些信息将解决酶结构变化如何导致酶功能差异以及这些变化如何在植物代谢背景下演变的重要问题。该项目将影响对酶功能进化的理解，特别是关于酶如何开发新功能。这反过来将影响对导致植物界复合多样化并最终导致生物圈植物多样性的因素的理解。该项目还将产生可用于更好地定制目标植物中特定化合物的生产的信息，从而提高生产“设计植物”的能力。本科生和高中教师将与博士后一起参与这项研究。高中教师（由暑期实习支持）将把纯化的PKS蛋白质带到教室，然后与学生一起将这些蛋白质结晶。这些蛋白质将包括酶的改变形式，这些蛋白质将用于探索酶类的结构和功能问题，以及控制容易结晶的蛋白质，这样学生将有一个成功的经验。因此，高中教师和他们的学生将直接在一个研究项目上工作，这个项目将有关于酶功能的潜在重要发现，他们将在这个过程中学习结构生物学。

Two large and important questions in plant metabolism are: what are the mechanisms that lead to the large array of compounds produced by plants and how do these mechanisms evolve? Ginger and turmeric contain a large array of compounds that are similar in structure and that appear to be produced by the same biochemical pathway. These compounds, including curcumin, other diarylheptanoids, gingerols and gingerol-like compounds, are produced by polyketide synthase-like enzymes (PKSs). Because these two species produce such a large array of related compounds, they are an ideal system to use to study the molecular and structural basis for differences in production of such compounds in plants. These compounds were chosen as the focus of this project because of their importance to plant defense, to plants' adaptation to the environment, and to human health, and because a large set of genes (41 in total so far) have been identified in ginger and turmeric related to but distinct from known PKSs (such as chalcone synthase) that are expressed differentially between tissues and developmental stages of the two species. This project will focus on identifying which specific members of this gene family are responsible for production of specific curcuminoids, gingerols, other diarylheptanoids or gingerol-related compounds. It will also determine the biochemical function of individual PKSs in ginger or turmeric. This project will then determine the structural basis for differential activity among the different PKSs. This information will address the important questions of how changes in enzyme structure lead to differences in enzyme function and how these changes evolve in the context of plant metabolism. Broader Impacts This project will impact understanding of the evolution of enzyme function, especially with regard to how enzymes develop new functions. This in turn will impact understanding of factors that lead to compound diversification in the plant kingdom and ultimately to plant diversity in the biosphere. This project will also produce information that could be used to better tailor the production of specific compounds in target plants, increasing the ability to produce "designer plants". Undergraduate students and high school teachers will work with post-doctoral fellows in this research. The high school teachers (supported by summer internships) will take purified PKS proteins to their classrooms and then will work with their students to crystallize these proteins. These proteins will include altered forms of the enzymes, which will be produced to probe the questions of structure and function in this enzyme class, as well as control proteins that easily crystallize, so that the students will have a successful experience. Thus, the high school teachers and their students will work directly on a research project that will have potentially important findings regarding enzyme function, and they will learn about structural biology in the process.